Vehicular wheels are often times mounted to a suspension arrangement which involves a spindle or steering knuckle that is configured to engage with upper and lower ball joint assemblies of a suspension control arm. Due to the multiple-point connectivity of the control arm to the steering knuckle, manipulation of the orientation of the upper portion of the control arm relative to the lower portion thereof acts to modify the wheel orientation relative to the vehicular frame. Such wheel orientations are known as camber and caster.
Wheel alignment adjustment in such suspension systems may be accomplished through a variety of methods and mechanisms. A common example mechanism involves eccentric devices, such as offset ball joints and offset bushings at one or more of the ball joint shafts. Caster/camber modifications may be effectuated through rotation of such eccentric devices, which relatively reposition the upper and lower ball joints.
An example conventional ball joint bushing used in connection with pinch bolt-type axle arm connections at the upper ball joint is illustrated in FIG. 1, wherein upper ball joint 10 includes a ball joint stud 12 extending up from steering knuckle 14. Upper control arm 16 includes a pinch bolt securement arrangement, wherein coupling end 18 of upper control arm 16 includes a slot 20 that may be operably compressed by bolt 22 extending through coupling end 18 of upper control arm 16. The conventional arrangement of FIG. 1 includes a ball joint bushing 24 having a central bore 26 through which ball joint stud 12 is operably inserted. Bore 26 may or may not be eccentric to a longitudinal axis defined by bushing 24.
An isolation view of bushing 24 is illustrated in FIG. 2, wherein tab 28 is clearly visible radially extending from bushing 24. Tab 28 is typically integrally formed with bushing 24, and is therefore immovable with respect to bushing 24. As shown in FIG. 1, tab 28 is configured to be at least partially received in slot 20 of coupling end 18. As such, tab 28, as well as the integrally connected bushing 24, may be secured to coupling end 18 of upper control arm 16 through compression of slot 20 by the actuation of bolt 22. Compression of slot 20 frictionally secures tab 28 between the opposed faces of coupling end 18 defining slot 20, and such frictional securement correspondingly secures bushing 24 about ball joint stud 12. Tab 28 may include a recess portion 29 through which bolt 22 may operably extend.
Because of the integral relationship described above between tab 28 and bushing 24, wheel alignment is limited to the one position afforded through the orientation of bushing 24 when tab 28 is positioned in slot 20. In some cases, vehicular modifications are made which necessitate adjustment to original wheel alignment. Such vehicular modifications include suspension changes and changes to the vehicle itself, such as modifying origination chassis arrangement to serve specific purposes. Such chassis modifications may include, for example, ambulance, utility truck, and conversion packages which significantly alter the weight distribution upon the chassis, and can thereby alter wheel alignment out of desired specifications. One solution for adjusting wheel alignment back within desired specifications has involved the use of replacement ball joint bushings, such as that illustrated in FIG. 3. Typically, conventional replacement ball joint bushings 40 do not have a tab extending radially therefrom, such as tab 28 in bushing 24, and instead are merely held in place within aperture 21 of coupling end 18 through the compressive action provided by bolt 22. The lack of a tab, such as tab 28, at bushing 40 enables various camber and caster adjustments to be made simply by rotating bushing 40, with its offset bore 46 about an axis defined by ball joint stud 12. Thus, replacement bushing 40 enables wheel alignment adjustment in various degrees without the need for replacement of the ball joint bushing.
In some cases, however, the lack of a tab extending from bushing 40 can result in displacement over time of the bushing position with respect to ball joint stud 12. Such displacement can include rotational and axial movements. In some cases, such displacement can dislodge bushing 40 out from an installed position in coupling end 18 altogether. Such an occurrence can result in major wheel misalignment, and even unsafe vehicular steering conditions.
In view of the above, therefore, it is a principle object of the present invention to provide an alignment apparatus which enables selective alignment adjustment without disassembly of the ball joint while being retainable in a predetermined secure position.
It is a further object of the present invention to provide a ball joint bushing that can be removably locked in a predetermined alignment position, while also enabling selective further adjustment of wheel alignment, including camber and caster adjustment.
It is a still further object of the present invention to provide a wheel alignment apparatus utilizing a ball joint bushing which is configured for replacement of original vehicular equipment, and which bushing enables secure selective wheel alignment adjustment.